Al/GaSb contact with slow positron beam

Abstract

Annealing study of the Al/GaSb system was performed by using a slow positron beam and the measurement of X-ray diffraction. The S parameter against positron energy data were fitted by a three layer model (Al/interface/GaSb). It was found there was a ∼5 nm interfacial at the region between the Al layer and bulk in the sample of as-deposited. After the 400°C annealing, this interfacial region extends to over 40 nm and S parameter dramatically drops. This is possibly due to a new phase formation induced by the atoms' inter-diffusion at the interface. The annealing out of the open volume defects in the Al layer was revealed by the decrease of the S parameter and the increase of the effective diffusion length of the Al layer. Annealing behaviors of Sb and Lb, of the GaSb bulk showed the annealing out of positron traps at 250°C. However, further annealing at 400°C induces formation of positron traps, which are possibly another kind of V Ga-related defect and the positron shallow trap GaSb anti-site. The results of the X-ray diffraction experiment verified the conclusion of obtained by using positron technology. © 2006 Chinese Physical Society.